The present invention relates to a sign comprising a stand; two pairs of first and second parallel support elements secured to the stand; a fabric with edge sections and between them a sign surface for information, extending in a plane between the support elements, and bars around which the edge portion of the fabric are wrapped and by means of which bars the edge portions of the fabric are detachably joined to the support elements, at least the first support element in each pair of support elements comprising a frame profile connected to the stand, and a clamping profile to support said bar provided with said edge portion of the fabric, said frame profile being provided with at least one counter support arranged at an outer edge portion of the frame profile located near the plane of the fabric in order to form a center of pivot for the clamping profile, the latter being provided with a flange arranged at an outer edge part of the clamping profile located near the plane of the fabric and defining an assembly pocket for receipt of the bar with the edge portion of the fabric wrapped around it via an opening, the clamping profile also being provided with a support member arranged to be brought into engagement with said counter support to permit pivoting of the clamping profile in relation to the frame profile about said center of pivot to a final position behind the plane of the fabric while clamping the fabric in relation to the second one of the two support elements, said second support element comprising a flange and an assembly pocket formed thereby and having the same shapes and functions as the equivalent elements of the first support element.
The European patents EP-0 114 453 and EP-0 268 308 describe signs in which the outer edges of the fabric are wrapped around retaining bars which are thereafter inserted in a recess in each of a plurality of fabric-retaining elements adjustably secured by bolts to the rod-shaped frame profiles. When the bolts extending through a vertical flange on each fabric-retaining element are tightened, the fabric is stretched. The frame-profile rods are provided with a longitudinal slit facing the fabric, the opposing sides of the slit having longitudinal grooves or ridges to provide a grip for the thread of each bolt. Such an arrangement for tensioning the fabric requires holes for the bolts to be drilled or punched in the flanges of the fabric-retaining elements, as well as the use of bolts requiring a certain amount of time for assembly and adding considerably to the material and assembly costs of a tension-fabric sign.
Signs with a different system of frame profile rods are sold under the name of Signcomp Tensioning System by Designtone Limited, England. The design of the frame profile rods here is even more complicated and includes at least one, but in some case two, longitudinal closed channels, which makes them expensive to manufacture. When the fabric is to be tensioned its edge is folded over a bar, short in relation to the length of the fabric, having a shallow U-shaped cross section, and an extremely complicated clip is snapped over it. The ends of the clip are provided with longitudinal teeth and are intended to be inserted laterally into a longitudinal open channel arranged in the frame profile rod. The cross-sectional dimensions of the channel are designed to suit the clip and one side of the channel is provided with teeth or ridges to cooperate with the teeth on the clip. The fabric is tensioned by pressing the clip into the open channel with the aid of a tensioning tool, and the tension in the fabric inclines the clip in the channel so that the fabric is firmly clamped between the clip and the opposing side of the channel.
Signs with a similar sign assembly are known through the patent specifications U.S. Pat. No. 4,937,961 and U.S. Pat. No. 5,033,216. However, the clips are manufactured by punching a blank out of resilient sheet metal and bending the punched blank. Instead of the longitudinal teeth at the ends of the clips, a fold bent along the entire length has the same function. Furthermore, the relatively short strip with shallow U-shaped cross section has instead a substantially rectangular cross section with one long side edge symmetrically bevelled and the other surfaces having longitudinal ridges located close together.
The patent U.S. Pat. No. 4,265,039 describes a sign with support elements, each of which has a plurality of short clamping devices and cooperating locking devices. Each clamping device is provided with an assembly pocket of circular form and an opening directed obliquely to the plane of the fabric. The opening is defined by two opposing flanges and its width is less than the thickness of the locking device, the latter thereby being retained inside the assembly pocket. The locking device consists of a cylindrical sleeve to be surrounded by an edge portion of the fabric which runs in to and out of the assembly pocket to be firmly clamped by the sleeve against the flanges when the sheet is tensioned. The locking sleeve is inserted into the assembly pocket from the side. The arrangement entails a complicated assembly of first the edge portions of the fabric and then the locking sleeves which are inserted in folds of the edge portions of the fabric which are difficult to maintain until the locking sleeves are in their operative positions. It will be seen that the tension force will be unevenly distributed along the fabric since it is clamped pointwise and not continuously, the fabric thus having folds or wavy portions. The arrangement also entails complicated retensioning of the fabric since it must be released pointwise at each locking sleeve which must be disengaged from its operative position, i.e. completely removed from the fabric and assembly pocket. The assembly procedure cannot be automated for a sign described in this U.S. patent.
Purely generally it can be stated that tension-fabric signs have been known for several decades. However, it is only recently that they have begun to be used more generally since both the fabric material and the assembly system for tensioning the fabrics have been improved. However, the known assembly systems and the frame profile rods used for them are relatively complicated and this is reflected in the cost of a finished tension-fabric sign. The work of retensioning the fabrics is also complicated.
The object of the present invention is to provide a sign enabling lower manufacturing and assembly costs, simpler retensioning of the fabric and having continuous engagement between fabric and clamping profiles so that the fabric remains uniformly tensioned.
The sign according to the present invention is characterized in that in its said final position the flange and assembly pocket of the clamping profile extend in a direction forming an angle of from 0.degree. to 180.degree. with the plane of the fabric; that the assembly pocket has an inner stop for the bar with the edge portion of the fabric wrapped around it spaced from the opening; that the depth of the assembly pocket, measured between the opening and the stop is less than the width of the bar so that an outer edge of the bar is located at a predetermined distance from and outside the opening; and that the fabric is arranged so that a section thereof extends around the outer edge of the bar and over a free edge of the flange in order in stretched state to press the bar with the edge portion of the fabric wrapped around it against the stop to clamp the edge portion of the fabric between the bar and the stop.